James bewshee



(No Model.) J. BEWSHER STEAM BOILER SAFETY PLUG; No. 375,041. Patented Dec. 20, 1887.

WITNESSES:

N PETERS PhowLnnngmpher, Wnhinglun. D, C

UNITED STATES PATENT OFFICE.

JAMES BEYVSHER, OF KANSAS CITY, MISSOURI.

STEAM-BOILER SAFETY-PLUG.

SPECIFICATION forming part of Letters Patent No. 375,041, dated December 20, 1887.

Application filed January 21, 1837. Serial No. 224,978. (No model.)

.To aZZ whom it may concern.-

Be it known that I, JAMES Bnwsnna, a citizen of the United States, residing at Kansas City, in the county of Jackson, in the State of Missouri, have invented a new and useful Improvement in Steam-Boilers, of which the fol lowing is a specification.

My invention relates to an improvement in safety attachments for steam-boilers.

The object of my invention is to provide a safety attachment for steam-boilersin which a fusible plug is employed, and which shall be simpler and cheaper to manufacture and more efficient in operation than attachments of this class heretofore in use.

With these ends in view my invention consists in providing a steam-boiler with a steam and water circulating duct passing through the firebox, and having its opposite ends opening into the boiler, in combination with a fusible plug located in said duct, for the purpose as will hereinafter appear.

In the accompanying drawings, Figure 1 is a cross-section of a horizontal tubular boiler, showing the ends of the duct passing into the boiler on the opposite sides. Fig. 2isa crossscction of a horizontal tubular boiler, showing both ends of the steam and water duct passing into the boiler on the same side; and Fig. 3 is a longitudinal section of a locomotive-boiler, showing the ends of the duct passing through the crownsheet into the boiler.

Similar letters referto'similar parts throughout the several views.

The reference-letter A represents a common steam-boiler, in which G represents the average water-line, and H the line below which it isdangerous for the water to fall. The steam space above the water is designated by the reference-letter F.

The before-mentioned steam and water duct is composed of a supp1ypipe, B, which enters the boiler at or near the dangerline H, and a discharge pipe, E, which enters the boiler above the pipe B, and a short distance above the average water-line, G. This steam and water duct is intended to extend through'the fire-box, and is provided at a point directly over the fire with a chamber, 0, in the lower part'of which is located a fusible plug, D.

The operation of my device is as follows: The boiler having been filled with water to any desired height above the danger-line H,

the fire is started, and the water commences to circulate through the steam and water duct, entering at pipe B passing through chamber 0 and over plug D and discharging out of pipe E into the boiler. This circulation of water over plug D prevents it from being melted by the action of the fire heating the same, but should the water be permitted to fall below the danger-line H, then the steam and water-duct would soon becdme emptied of water and the action of the fire on plug D would rapidly melt the same, and thus leave a free passage for the steam to enter the fire-box and immeately extinguish the fire and prevent the explodingor burning of the boiler. x

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. A steam boiler provided with a water and steam circulating duct passing through the firebox or in direct contact with the products of combustion of the fire, and having its ends communicating with the interior of the boiler, in combination with a fusible plug lo cated in that portion of the pipe which comes in contact with the products of combustion of the fire-box, substantially as set forth.

2. A steam-boiler provided with a water and steam circulating duct passing through the fire-box, and having its opposite ends communicating with the interior of the boiler and extending one above the other, in combination with a fusible plug, substantially as described.

3. A steam-boiler provided with a water and steam circulating duct passing through the upper part of the fire-box, and having its ends opening into the interior of the boiler, in combination with a fusible plug located in the duct directly over the fire, substantially as described.

JAMES BEWSHER.

WVitnesses:

L. E. WYNE, D. M. QUAY. 

